Method of froth flotation ore separation



Patented July 21, 1936 UNITED STATES PATENT OFFICE IHETHOD F FROTH FLOTATION ORE SEPARATION Frederic A. Brinker, Denver, C010.

No Drawing. Application March 29, 1932, Serial No. 601,886

4 Claims. (Cl. 209167) This invention relates to improvements in differential froth flotation process for use on ores containing copper and in which a separation is to be effected between copper sulfide and other sulfides. I have discovered that copper sulfide minerals can be inhibited so that other sulfides pulp in the presence of the cyanide compound;

The cyanide compound will be one capable of inhibiting copper sulfide minerals, for example sodium cyanide or zinc cyanide. The lead com-' pounds may be any of the soluble lead salts, such as lead nitrate and lead chloride. The inhibition of copper sulfides by cyanide has resulted heretofore in using less cyanide on copper ores than on lead and zinc ores, because with copper ores any appreciable amount of cyanide has resulted in a loss of inhibited copper sulfides which remained in the tailings. When treating this type of ore the copper sulfides are reactivated by the use of lead compounds after reduction with sulfur dioxide in the presence of cyanide compounds as described above.

A typical example of this invention is as follows:

flde, zinc sulfide and iron sulfide, the ore is ground with water to liberate the sulfides from each other and from any gangue present in the ore. This ground ore pulp is subjected to a conditioning period which may be very short, or of varied duration, in which a reducing condition is present together with a cyanide compound such as zinc cyanide or sodium cyanide.

This conditioned pulp is now subjected to a froth flotation treatment in which lead sulfide is floated by any of the well known lead promoters and frothers such as sodium aerofioat, which is a til-substituted dithiophosphate and cresylic acid in the presence of the inhibited or depressed copper sulfide mineralsand also in the presence of inhibited zinc or iron sulfide minerals. The pulp from the lead flotation step is next treated by the addition of a lead compound such as lead nitrate, lead chloride or other soluble lead com- In an ore containing lead sulfide, copper sul- D und which reactivates the copper-sulfide minerals which are then floated off in a froth by the addition of any of the well known copper collecting and frothing agents such as the above mentioned aerofioat or cresylic acid. This is done 5 in the presence of the inhibited zinc and iron sulfide. Next the pulp is subjected to a treatment .with copper sulfate or other zinc reactivating chemicals and subjected to a froth separation treatment in which the zinc sulfide is floated in the presence of the inhibited iron sulfide. At this point the iron sulfide can either be rejected as tailing or can be floated by any of the well known methods for floating iron sulfide.

Another example of this invention is as follows:

In an ore containing copper sulfide and iron sulfides it is desired to make a sharp separation by the froth flotation process between the copper sulfides and the iron sulfides. In this case the ore is ground with water to liberate the sulfides from each other and from the gangue present in the ore and a cyanide compound is added either to the grinding mill so as to be present during grinding; or the cyanide compound is added to the ground ore pulp prior to the flotation operation. 5

This cyanide compound is a well known inhibitor for iron sulfides, but if sufiicient cyanide is used to give the best results for the inhibiting of the iron sulfides, some copper sulfides will be inhibited by this cyanide resulting in a high tailing loss of copper sulfide. Therefore, prior to the flotation operation in which the copper sulfides are separated from the iron sulfides, a lead compound is added to the ore pulp to reactivate the copper sulfides inhibited by the cyanide compound. This ore pulp is next subjected to the froth flotation treatment in which a flotation promoter and frother (as mentioned 'above) are added and the copper sulfides removed in a froth concentrate, thereby making a sharp separation between the copper sulfides and iron sulfides. After this separation the iron sulfides can either be rejected as tailing or can be floated by well fnnwn methods to make an iron froth concenra e.

Having described the invention what is claimed as new is:

1. In the froth flotation treatment of ores the step of treating ores containing copper in the presence of sulphur dioxide with a cyanide compound and then subjecting the resulting pulp to the tdifferential froth flotation separation treatmen a 2. A method according to claim 1 and the additional steps of adding to the residual pulp a 55 soluble lead salt to reactivate copper sulfides, and froth floating said copper sulfides.

3. A froth flotation method for the separation of ores containing lead and copper sulfides comprising subjecting an ore pulp to the action of a cyanide compound and providing chemical reducing conditions to inhibit the flotation of copper sulfide minerals, subjecting the pulp to froth flotation to float out the lead sulfide minerals, adding a soluble lead compound to the resulting pulp capable of reactivatlng the copper sulfide minerals, and removing the copper sulfide minerals by froth flotation, sulfur dioxide being used to produce the chemical reducing condition.

aoaasro FREDERIC A. BRINKER. 

